Low birth weight (especially less than 3.3 pounds, or 1.5 kilograms)

Low Apgar score (lower than 5 at 1 minute or lower than 7 at 5 minutes after birth)

Low blood oxygen levels or seizures resulting from a difficult delivery

Infection before birth with rubella, syphilis, herpes, cytomegalovirus, or toxoplasmosis

Abnormalities in the skull or face, especially those involving the outer ear and ear canal (see Developmental Abnormalities of the Outer Ear)

A high level of bilirubin (a waste product) in the blood (see Jaundice in the Newborn)

Bacterial meningitis (see Meningitis in Children)

Bloodstream infection (sepsis)

Use of a ventilator (a machine that helps air get in and out of the lungs) for a long time

Use of certain drugs, such as aminoglycoside antibiotics and some diuretics

History of early hearing loss in a parent or close relative

A head injury with a skull fracture or loss of consciousness

Chronic middle ear infections or a cholesteatoma

Some neurologic disorders, such as neurofibromatosis and neurodegenerative disorders (such as Hunter syndrome)

Exposure to noise at high levels or for long periods

Perforation of the eardrum due to infection or injury